1. Field of the Invention
This invention pertains to expansible chamber devices. More particularly, this invention pertains to the cylinder details of such devices with coaxial cylinders. The subject invention also pertains to the filed of ordnance; more particularly to the shape and composition of a projectile defeating element.
2. Description of the Prior Art
It is known to provide redundancy in a hydraulic actuator system by providing two or more hydraulic cylinder assemblies connected to a common element to be positioned thereby. Each assembly is connected to an independent source of hydraulic pressure so that, in the event of leakage caused by damage to one assembly, another assembly can continue to actuate the element. It is also known to avoid jamming of such an actuator due to the projection of "petals" from a penetrated cylinder wall of one assembly into the path of a piston thereof by constructing the wall of material which is relatively thin and weak so that petals therefrom are shearable by engagement of the piston under the urging of the normal hydraulic pressure in one or more undamaged cylinder assemblies.
Certain prior art devices, although effective in resisting ballistically caused jams, were relatively heavy and expensive. Other known devices employ a hydraulic cylinder assembly having a tubular cylinder wall, which is incapable of withstanding without reinforcement the normal hydraulic operating pressure, together with a layer externally of the wall of resin impregnated filament, preferably graphite filament, which reinforces the wall. To reduce weight in such a construction it is desirable that the filament be arranged to reinforce the tubular wall against axial as well as circumferential stress. Reinforcement against axial stress can be effectively provided by wrapping the filament transversely of the tube about elements closing the tube ends. However, it is evident that repair of elements internal to the tube, such as pistons and seals, is not practical once the impregnated filament layer is applied.